Hi look for the recommondation of the lightcompany. Otherwise you got to test it. The very young seedlings dont need big lights until they are 3 weeks old. Go with the lower wattage in the beginning. And you got to check out the distance. if youtr girls get leggy its to far away
Or later if you go with the higher wattage, you see that you got the right distance if there is a good space between the nodes, if they are to close together you got to rise the light( or lower wattage)
Take care look for lightburn................................................
For seedlings i use 2x26 Watt led very close to them. But every grower does it different. But never to near and full power